Resistive and capacitive sensors are widely used in biomedical applications to measure various parameters such as flow, pressure, temperature, and chemical species like glucose, protein and DNA. A conventional sensor interface typically consists of an analog front-end (AFE), a programmable gain amplifier (PGA) and an analog-to-digital converter (ADC). Such a conventional sensor interface may provide good performance in terms of sensing resolution and dynamic range, but it is not able to reduce its power and silicon area consumption to a level which is desirable in biomedical applications. A known approach to address this constraint is to convert the sensor output into a form of frequency by using an oscillator circuit. A typical choice of oscillator for this application is an RC type, which features small silicon area and low power consumption when compared with its LC type counterpart. Among RC oscillators, relaxation oscillator (ROSC) is preferred due to its constant frequency tuning gain and continuous phase readout. However, a major problem associated with ROSC is its poor phase noise and jitter performance. This reduces the resolution of the RC relaxation oscillator (RCOSC) based sensor interface. Accordingly, it is desirable to provide a low power high resolution RCOSC based sensor interface.